Substantial progress has recently occurred in creating atomic distributions that vary over small length scales. In atomic beams, such distributions have been created by diffraction, periodic spatial modulation, channeling, focusing, and cooling. In general, the distributions exhibit momentum-space coherence and are of both practical and fundamental interest. Recently, techniques have been developed for precise velocity selection which are complementary to the techniques of the present invention. See. e.g., Kasevich et al., Phys. Rev. Lett. 66, 2297 (1991). Important applications include atomic interferometry, gyroscopes, and the creation of submicron structures by atomic deposition. See. e.g., Martin et al., Phys. Rev. Lett 60, 515 (1988); Chebotaev et al., J. Opt. Soc. Am. B 2, 1791 (1985).
While techniques exist to create suboptical wavelength atomic spatial modulation and interference in atomic beams, methods for detection have been limited principally to hot wires or mechanical slits, which are relatively crude devices. The only use of optical absorption to determine an atomic position distribution has been by channeling atoms in an off-resonant optical standing wave. See Salomon et al., Phys. Rev. Lett. 59, 1659 (1987).
Optical methods such as those disclosed in the instant application are ideally suited for high-resolution resonance imaging because they permit the study of very small volumes, which facilitates the application of large spatially varying potentials. Further, optical techniques do not require mechanical surfaces (wires, slits, electrodes, etc.) to be placed in the region to be studied and thus the atomic beam is not destroyed.